There exist several well known high temperature spray methods in the industry today. Most use a high temperature, open flame into or through which is passed a metal substance which is capable of being melted by the flame and sprayed by the apparatus onto a substrate. Frequently, this type of flame spray operation is used to repair or rebuild worn metal parts such as turbine blades or shafts, etc. The molten metal sprayed by the apparatus coats and fills any cracks or eroded portions of the metal substrate so that the replacement of the entire structure is not required.
One problem with such a flame spray system is that the spray does not always coat only those portions which need the metal. Depending upon the conditions of the equipment, the operator and the substrate being treated, areas surrounding the worn substrate are coated with the molten metal to some degree. At the very least, this is uneconomical in that the metal is being applied to a portion of the surface where it is not needed. More often, it is a hindrance and should be removed for aesthetic reasons. In the worst case, the additional metal upsets the mechanics of the device and therefore the metal must be removed, e.g. in a jet turbine, the additional metal on a turbine blade could upset the balance and thus the performance of the turbine.
A mask formed of metal has been used to cover the area surrounding that which is to be treated. Unfortunately, such a mask is difficult to make and must be custom manufactured for each application.
The present invention provides an improved mask for such high temperature and/or open flame spraying processes, which is inexpensive and may be easily custom formed to the desired configuration.